Bluetooth® Core Specification Version 5.0 Feature …

1 bluetooth Core Specification Version Feature EnhancementsBluetooth Core Specification Version includes several primary updates. This document summarises and explains each change. Author: Martin WoolleyVersion: Date: 9 September | 2 Revision October 2017 Martin WoolleyInitial September 2021 Martin WoolleyFormat | 3 Table of ContentsAt a Glance ..5LE 2M PHY ..5LE Coded PHY ..5 Extended Advertising ..5 Slot Availability Mask ..6 Improved Frequency Hopping ..61 . The LE 2M and LE Coded PHYs .. Background .. About the LE 2M PHY ..7 Capabilities and Benefits ..7 Example Use Cases .. About the LE Coded PHY ..8 Capabilities and Benefits ..9 Understanding Range ..9 Dealing with Errors ..10 Error Detection ..10 Error Correction .. Host Controller Interface (HCI) .. Comparing the three LE PHYs ..122.

2 Extended Advertising .. Background .. About Extended Advertising .. | 4 Table of Contents Capabilities and Benefits ..15 Larger Packets and Advertising Channel Offload ..15 Advertising Packet Chaining ..15 Advertising Sets ..15 Periodic Advertising .. Additional changes to bluetooth LE advertising Comparing Legacy Advertising and Extended Advertising ..173 . Slot Availability Mask .. Background .. About Slot Availability Mask ..19 Capabilities and Benefits ..19 Technical Highlights ..194 . Improved Frequency Hopping .. Background .. About Improved Frequency Hopping ..21 Capabilities and Benefits ..21 Technical Highlights ..21 References ..22At a GlanceLE 2M PHYThe bottom layer of the bluetooth Low energy (LE) stack is called the Physical Layer. Particular configurations of the physical layer are often referred to as a PHY.

3 bluetooth Core Specification Version adds a new way in which the physical layer may be used with a PHY called LE 2M. The LE 2M PHY uses a symbol rate of 2 mega-symbols per second which given that bluetooth technology uses a binary modulation scheme is equivalent to 2 megabits per second at the physical layer. LE 2M makes higher application data rates Coded PHYA further PHY, designed to support longer range communication has been defined in Version of the bluetooth Core Specification . It is called the LE Coded PHY and uses a technique called Forward Error Correction (FEC) to enable longer range communication without any need to increase transmission power. Extended AdvertisingBluetooth LE can perform connectionless communication using a procedure called advertising. Legacy advertising uses three channels from the GHz radio band, specifically channels 37, 38 and 39.

4 bluetooth Core Specification Version introduces extended advertising which uses all 40 bluetooth LE channels, providing better spectral efficiency, scalability and reduced vulnerability to reliability issues which can be caused by packet collisions in busy radio environments. Extended advertising allows more data to be transmitted in a single packet and even larger application layer payloads to be fragmented and then transmitted in a series of chained packets. It also supports a new concept called periodic advertising which involves advertising packet transmission taking place at precisely timed intervals and provides a mechanism for observer devices to discover the advertising device s periodic advertising schedule and to then synchronise their scanning with | 5back to contents Logical Link Control & Adaptation ProtocolFigure 1 - The bluetooth Low energy stackback to contents | 6 Finally, extended advertising allows multiple advertising configurations to be active at the same time through a capability known as advertising Availability MaskThe Mobile wireless Standard (MWS) radio bands used by 4G LTE in smartphones can interfere with bluetooth radio communication when the two systems are collocated in the same device.

5 A new bluetooth BR/EDR Feature called the Slot Availability Mask (SAM) helps mitigate this issue by allowing the time slots used by the two radios to be Frequency HoppingBluetooth LE uses adaptive frequency hopping to spread communication across channels in the band. A new channel selection algorithm improves the way in which channels are selected and produces a greater degree of randomness and substantially more potential channel sequences. This improves both spectral efficiency and reliability in busy to contents | 71. The LE 2M and LE Coded PHYs1 .1 BackgroundIn a bluetooth LE stack, the lowest layer is called the physical layer. It is responsible for the representation of digital bits in analogue radio signals. A bit, when encoded in a radio signal is called a symbol. The physical layer encodes bits as symbols when transmitting data and decodes symbols to produce bits when basis for encoding digital information within a radio signal is called a modulation scheme.

6 bluetooth LE uses a modulation scheme called Gaussian frequency shift keying which in simple terms involves shifting a central carrier signal up by a small frequency deviation to represent a digital value of one or down by the same frequency deviation value to represent a digital zero. The frequency shifted signal is then transmitted for a certain period of time and this constitutes a single transmitted symbol. The number of symbols that can be transmitted per second is called the symbol rate and this is a property of the implementations of bluetooth LE must include a PHY called LE 1M which operates at a symbol rate of 1 mega-symbol per second. At the application layer, a data rate of up to approximately 800 kilobits per second is possible when using LE 1M depending on other parameters and packet scheduling details established by the .2 About the LE 2M PHYB luetooth Core Specification Version introduced a new PHY called LE Capabilities and BenefitsThe LE 2M PHY operates at a symbol rate of 2 mega-symbols per second.

7 This is double the symbol rate of the mandatory LE 1M PHY. The same data, transmitted in the same number of packets and using the LE 2M PHY rather than the LE 1M PHY will use half the radio airtime since the same number of symbols will be transmitted but at twice the rate. This represents a significant benefit in improved spectral the application layer, a data rate of up to approximately megabits per second is possible1 when using LE 2M depending on other parameters and packet scheduling details established by the implementation. 1 .2 .2 Example Use CasesMany use cases involving bluetooth LE tend to involve small amounts of data, perhaps transmitted only occasionally. But there are use cases gaining prominence which demand a low-power wireless communications technology which supports higher data rates. 1 sources: Novel Bits and Nordic to contents | 8 Firmware upgrades are an important practice which as well as delivering new functionality, will often deliver bug fixes and security improvements which help keep users, businesses, and industrial systems safe and secure.

8 Being able to initiate and complete a firmware upgrade over the air quickly helps with the task of keeping device firmware up to date. Consumers in particular are likely to be reluctant to apply firmware updates if their experience is that they take an excessive amount of time to complete. User experience and human behaviour are as much a consideration in security as are the technical and fitness devices are getting increasingly sophisticated and now often measure multiple dimensions of the human body more frequently and with greater accuracy. A similar trend is taking place with some medical devices. The ECG has evolved from a device which had one lead to the 12 lead ECG of today. Such changes bring with them a substantial increase in the amount of data being has also been a rise in devices that act as buffered sensors, especially in fields like Lifestyle Analysis where the user will wear a sensor, often for several days, before transferring all the accrued data to another device such as a smartphone or of data is not the only driver behind the introduction of LE 2M.

9 Transmitting a given amount of data using a reduced amount of airtime also provides better spectral efficiency and requires less .3 About the LE Coded PHYThe original LE 1M PHY has a much longer range than is popularly believed to be the case. Informal testing by the author, using a standard smartphone, a bluetooth LE microcontroller unit (MCU) and the LE 1M PHY demonstrated the successful receipt of bluetooth notifications by the smartphone at a distance of over 350 metres from the MCU in an environment which was sub-optimal with respect to radio communication, containing numerous people and trees. And there are commercial Bluetooth2 See Figure 2 - We re collecting more data from sensorsFigure 3 - Informal testing of bluetooth range using LE 1M PHY: miles = 354 to contents | 9 modules on the market whose data sheets state that a range of 500 metres is the fact that the LE 1M PHY has a remarkably healthy range for a low-power wireless communications technology, why increase it still further?

10 There are many use cases where greater range can be advantageous. The smart home sector is one example and it, to a degree, led to the effort to introduce the long range LE Coded Capabilities and BenefitsThe LE Coded PHY, also commonly referred to as bluetooth Long Range allows range to be approximately quadrupled compared to the original LE 1M PHY, and this has been accomplished without increasing the transmission power .3 .2 Understanding RangeTo understand how range has been so dramatically increased without a need for a corresponding increase in transmission power requires the question of what we mean by range in wireless communications systems to be is a radio technology and radio is a form of electromagnetic radiation. In the context of telecommunications, the question of maximum range is better expressed as what is the maximum range at which data can be correctly extracted from the received signal, rather than how far can this electromagnetic energy travel and still be distinction relates to how we use radio to encode and transmit data and how background noise can impact the decoding of that data by a radio receiver.